Toward Robot-Assisted Photoacoustic Imaging: Implementation Using the da Vinci Research Kit and Virtual Fixtures

Photoacoustic imaging of the prostate is challenging due to the limited access and limited acoustic windows to the prostate gland. We aim to develop intraoperative prostate photoacoustic imaging using the da Vinci robotic system and a pick-up ultrasound transducer that can be easily picked up and manipulated by the robot. We propose a new approach in which the da Vinci robot is programmed to acquire trajectories in a shared control configuration with “virtual fixtures”; the pick-up transducer is controlled so that it stays parallel to a single axis defined as the tomography axis, and its translation is fixed to a single plane normal to this axis. The surgeon controls the transducer motion on the tissue along this virtual fixture while the laser is fired and photoacoustic data are collected periodically. The RMS errors of the photoacoustic tomography images are 0.06 a.u. This study confirms that intraoperative da Vinci robot-assisted photoacoustic imaging with a pick-up transducer is feasible.